In Europe a tool from the Joint Research Center of the European Commission is also available:

https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html

The tool takes into account location, placement, horizon (if you upload a CSV file with the profile of the horizon in your installation location, to take into account shadows), efficiency of the solar panels and so on.

The tool can also suggest optimal tilt and azimuth for the specified location.